Fix for #8777

Now filter name is trimmed and lowercased before evaluation for case
insensitive and whitespace trimemd check.

Signed-off-by: Oh Jinkyun <tintypemolly@gmail.com>

pkg/parsers/filters/parse.go

@@ -29,7 +29,9 @@ func ParseFlag(arg string, prev Args) (Args, error) {
 	}
 
 	f := strings.SplitN(arg, "=", 2)
-	filters[f[0]] = append(filters[f[0]], f[1])
+	name := strings.ToLower(strings.TrimSpace(f[0]))
+	value := strings.TrimSpace(f[1])
+	filters[name] = append(filters[name], value)
 
 	return filters, nil
 }